Large magnetoresistance in rare-earth based alloys

The results of magnetoresistance (Δϱ/ϱ) measurements at low temperatures on the alloys, CeIr2B2, Pr0.2R0.8Cu2Ge2, Pr0.2R0.8Ni2Si2, and Pr0.2R0.8Cu2Si2 (R-La, Y), are reported. The Δϱ/ϱ of CeIr2B2 at 5 K (in the ferromagnetically ordered state) is large (-60%) at 70 kOe. In the case of Pr alloys, Δϱ/ϱ is positive thereby proving that the Kondo effect is absent in these alloys. One of the Pr alloys, Pr0.2La0.8Cu2Si2, also exhibits a large positive Δϱ/ϱ at 5 and 10 K about (28% at 70 kOe). Relevance of these findings to the current topic of interest on giant magnetoresistance will be pointed out